Synthesis and study of the structure of cage-like metallosiloxanes with pair combinations of 3d transition and alkaline earth metals

The selective replacement of Na ions in cage-like (Cu,Na) organosiloxanes in reactions with divalent metal halides was studied. The sandwich-like isomer [PhSiO2](6)Cu4Na4[PhSiO2](6) forms the corresponding bimetallic complexes [PhSiO2](6)Cu4M2[PhSiO2](6) (M = Cu, Zn, Mg, Sr, Ba) retaining a sandwich-like structure (in 60-90% yields) regardless of the metal ion size in MCl2. Under similar conditions, the reactions of the globular isomers [RSiO2](12)Cu4Na4 (R = Ph, Me, Vin) with CuX2 (X = Cl or Br) afforded insoluble polymer products. The reaction in dioxane or THF in the presence of DMSO gave the crystalline globular-type metal complexes [RSiO2](12)Cu-4[CuX](4), in which Na ions are replaced by CuX groups. The compositions and structures of the synthesized metal complexes were studied by X-ray diffraction, elemental analysis, and destructive silylation combined with gel permeation chromatography and H-1 NMR spectroscopy.